The present invention relates to an electronic device and a semiconductor device. The electronic device includes a mounting board mounted with multiple semiconductor devices and is used for communication terminals, for example. The semiconductor device includes a multiplexed terminal and is mounted over the electronic device. More particularly, the invention relates to a technology applicable to mobile telephones.
According to the technology disclosed in patent document 1, a first processor is provided with a memory subsystem. A second intermediate processor is inserted into a communication path between the first processor and the memory subsystem. A memory transaction is transmitted to the second processor. The memory transaction is controlled so as to reach the memory subsystem when the memory transaction is allowed to pass through the second processor. In short, the first processor supplies the memory with an access signal via the second processor to enable access to the memory.
According to patent document 2, a data-based interface circuit portion and a command/address-based interface circuit portion are blocked separately from each other along chi peripheral edges such that SDRAM is connected with a memory interface circuit for a microcomputer.    Patent Document 1. Japanese Unexamined Patent Application Publication (Translation of PCT Application) No. 2005-531863    Patent Document 2: Japanese Unexamined Patent Application Publication No 2008-153288